1. Reference to Earlier-Filed Applications
This application claims priority under Section 119(e) to: (a) U.S. Provisional Application Ser. No. 60/633,091 titled “Physical Layer Transmitter for Use in a Broadband Local Area Network,” filed Dec. 2, 2004; (b) U.S. Provisional Application Ser. No. 60/632,797 titled “A Broadband Local Area Network,” filed Dec. 2, 2004; (c) U.S. Provisional Application Ser. No. 60/633,002 titled “Multiple Access Controller for a Broadband Coaxial Network,” filed Dec. 2, 2004; and (d) U.S. Provisional Application Ser. No. 60/632,856 titled “Interface for a Broadband Coaxial Network,” filed Dec. 2, 2004, all of which are incorporated herein, in their entirety, by this reference.
2. Field of Invention
The invention relates to broadband communication networks and in particular to broadband communication networks utilizing coaxial cable.
3. Related Art
The worldwide utilization of external television (“TV”) antennas for receiving broadcast TV, and of cable television and satellite TV is growing at a rapid pace. These TV signals from an external TV antenna, cable TV and satellite TV, such as a direct broadcast satellite (“DBS”) system, are usually received externally to a building (such as a home or an office) at a point-of-entry (“POE”). There may be multiple TV receivers and/or video monitors within the building and these multiple TV receivers may be in signal communication with the POE via a broadband cable network that may include a plurality of broadband cables and broadband cable splitters. Generally, these broadband cable splitters distribute downstream signals from the POE to various terminals (also known as “nodes”) in the building. The nodes may be connected to various types of Customer Premise Equipment (“CPEs”) such as cable converter boxes, televisions, video monitors, cable modems, cable phones and video game consoles.
Within a typical home, there may be a mixture of coaxial cables of varying quality, such as RG-59, RG-6, RG-6 quad shield, creating at times a less than optimal RF environment within the coaxial cables. Further, typical homes do little or no termination of cable outlets and that results in the introduction of RF interference into the coaxial cables in the form of signal reflections and ingress. Another problem often encountered with typical home coaxial cable configurations is that of multiple splitters of varying quality and frequency response characteristics, which may create a problem for signal distribution and at times limit the use of the coaxial network for local area networking, thus requiring a more controlled or higher quality cabling and at times, higher frequency ranges.
Typically, these broadband cables and broadband cable splitters are implemented utilizing coaxial cables and coaxial cable splitters, respectively. Additionally, in the case of cable TV or satellite TV, TV receivers with cable or satellite converter boxes, also known as set-top boxes (“STBs”), are connected between the TV receivers and the broadband cable network.
Typically, a STB connects to a coaxial cable from a network node (such as the wall outlet terminal) to receive cable TV and/or satellite TV signals. Usually, the STB receives the cable TV and/or satellite TV signals from the network node and converts them into TV signals that may be received by the TV receiver and/or video signals that may be received by a video monitor.
In FIG. 1, an example known broadband cable network 100 (also known as a “cable system” and/or “cable wiring”) is shown within a building 102 (also known as customer premises or “CP”) such as a typical home or office. The broadband cable system 100 may be in signal communication with an optional cable service provider 104, optional broadcast TV station 106, and/or optional DBS satellite 108, via signal path 110, signal path 112 and external antenna 114, and signal path 116 and DBS antenna 118, respectively. The broadband cable system 100 also may be in signal communication with optional CPEs such as STBs 120, 122 and 124, via signal paths 126, 128 and 130, respectively.
In FIG. 2, another example of a known broadband cable system is shown within a building (not shown) such as a typical home. The cable system 200 may be in signal communication with a cable provider (not shown), satellite TV dish (not shown), and/or external antenna (not shown) via a signal path 202 such as a main coaxial cable from the building to a cable connection (not shown) outside of the building. The cable system 200 may include a multi-tap device 204 which allows signal distribution to neighboring homes, a POE 210 to the home, N:1 Splitters 214, 222, 230, and 234, and Node Devices 228, 250, 252, 254, 256, 258, and 260.
Within the cable system 200, the Multi-Tap 204 may be in signal communication with the POE 210 via signal path 208. The POE 210 may be the connection point from the cable provider which is typically located external to the building of the cable system 200. The POE 210 may be implemented as a coaxial cable connector, transformer and/or filter.
The N:1 Splitter 214 acts as the main splitter (sometimes also called a Root Node) and may be in signal communication with N:1 Splitter 222, Node Device 228, and N:1 Splitter 230 via signal paths 216, 218 and 220, respectively. The N:1 Splitter 222 may be in signal communication with Node Devices 250, 252, and 254 via signal paths 224, 225 and 226, respectively. The N:1 Splitter 230 may be in signal communication with Node Device 260 and N:1 Splitter 234, via signal paths 240 and 232, respectively, and N:1 Splitter 234 in turn may be in signal communication with Node Devices 256 and 258 via signal paths 236 and 238, respectively. The N:1 Splitters 214, 222, 230 and 234 may be implemented as coaxial cable splitters. The Node Devices may be comprised of numerous well known STB units such as cable television set-top boxes and/or satellite television set-top boxes, as well as various video and multimedia devices typically found in the home or office. Typically, the signal paths 208, 212, 216, 218, 220, 224, 225, 226, 232, 236, 238, and 240 may be implemented utilizing coaxial cables.
In an example operation, the cable system 200 would receive CATV, and/or satellite radio frequency (“RF”) TV signals 262 from the Multi-Tap 204 via signal path 208 at the POE 210. The POE 210 may pass, transform and/or filter the received RF signals to a second RF signal 264 that may be passed to N:1 Splitter (Root Node) 214 via signal path 212. The N:1 Splitter 214 may then split the second RF signal 264 into RF signals 230, 268 and 270. The RF signal 230 is then passed to N:1 Splitter 222 and the RF signals 272, 274 and 276 are passed to Node Devices 250, 252 and 254 via signal paths 224, 225 and 226, respectively. If the Node Device is a set-top box, the Node Device may convert the received RF signal into an RF signal such as Channels 3 and 4, or baseband signals such as Video and S-Video, or Components such as Y, Pr, Pb and Audio signals (not shown) that may be passed to a video monitor or a TV set (not shown) in signal communication with the set-top box.
In recent years, numerous consumer electronics appliances and software applications have been developed and continue to be developed. Thus, the numbers and types of CPEs that can be utilized in homes increase. These include television sets, video monitors, DVD players, Personal Computers (“PCs”), STBs, cable modems, cable phones, video game consoles, audio components, as well as various media units containing storage devices, such as Digital Video Recorders (DVRs) that are capable of storing various forms of multi-media information on a hard magnetic disk or optical drives for later retrieval and use by any device connected to it. Furthermore, there is a growing need for different CPEs to communicate with each other in the home and be able to share storage, display and other capabilities. As an example, users in a home may desire to simultaneously play network video games between different rooms in the home. Additionally, in another example, users in a home may want to share other types of digital data (such as video and/or computer information) between different devices in different rooms in a home.
Unfortunately, very few homes have home networks capable of providing the data rates and reliability required in order to allow video and audio networking within the home. Furthermore, most multimedia devices are not in the vicinity of the various home networking connection points, such as Ethernet or phone lines. For this reason, the existing coaxial cable within the home is a very attractive medium for providing such a networking functionality. The home coaxial cable has enormous amount of bandwidth available at frequencies not currently used by the cable TV services, it is a contained medium that mostly does not suffer external interference from other services such as the wireless medium, and most multimedia devices such as TV sets, STBs, DVRs, DVDs, and multimedia PCs are already connected to the home coaxial cable.
However, most broadband cable networks (such as the examples shown in both FIG. 1 and FIG. 2) presently utilized within most existing buildings are not configured to allow for easy networking between CPEs for several reasons: first, the devices that connect to the coaxial cable in the home are traditionally the Consumer Electronics (CE) and entertainment-related devices that have not traditionally been networked devices. This is about to change for the reasons stated above. The coaxial network is the ideal networking channel since these devices do not require any new connection since they are already connected to the coaxial network. Second, the coaxial network is already being used for TV distribution; hence one needs to ensure that utilizing it for networking does not impair existing services. Third, most broadband cable networks utilize cable splitters that are designed to split an incoming signal from the POE into numerous split signals that are passed to the different nodes in different rooms. These splitters have been designed to not allow or to minimize the signal transfer between output ports; thus the existing conventional wisdom is that the use of splitters in the existing broadband cable networks prevents networking between devices in the network because signals returning from the devices cannot be routed back through the splitters, i.e., cannot “jump” a splitter.
As an example, in a typical home the signal splitters are commonly coaxial cable splitters that have an input port and multiple output ports. Generally, the input port is known as a common port and the output ports are known as tap ports. These types of splitters are generally passive devices and may be constructed using lumped element circuits with discrete transformers, inductors, capacitors, and resistors and/or using strip-line or microstrip circuits. These types of splitters are generally bi-directional because they may also function as signal combiners, which sum the power from the multiple tap ports into a single output at the common port.
Presently many CPEs utilized in modern cable and DBS systems, however, have the ability to transmit as well as receive. If a CPE is capable of transmitting an upstream signal, the transmitted upstream signal from that CPE typically flows through the signal splitters back to the POE and to the cable and/or DBS provider. In this reverse flow direction, the signal splitters function as signal combiners for upstream signals from the CPEs to the POE. Usually, most of the energy from the upstream signals is passed from the CPEs to the POE because the splitters typically have a high level of isolation between the different connected terminals resulting in significant isolation between the various CPEs.
The isolation creates a difficult environment in which to network between the different CPEs because the isolation results in difficulty for transmitting two-way communication data between the different CPEs. Unfortunately, CPEs are becoming increasingly complex and a growing number of users desire to inter-connect these multiple CPEs into a network where one can share media and other functionality between connected devices.
Therefore, there is a need for a system and method to connect a variety of CPEs into a local network, such as a local area network (“LAN”), within a building such as a home or office, while utilizing an existing coaxial cable network within the building. Additionally, there is a need for the system and method to have the capability of allowing the user to incorporate a variety of newly-developed CPEs into the local network quickly and easily.